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Abstract Highly tunable dry adhesion has practical ramifications in robotic manipulation. While grippers based on mechanical interlocking and suction are adopted in various industries, soft grippers that can handle small and delicate objects reliably are yet to be invented. In this paper, it is reported that the presence of an adhesive substrate against a negatively pressurized soft hemispherical shell can significantly delay buckling of the shell. The net adhesion strength of such a depressurized shell can reach 60 times that of an open shell without any pressure difference. Simultaneous measurements of internal pressure, mechanical tension, contact area, and approach distance agree well with a semi‐analytical solid‐mechanics model. Introduction of defects at the polar region of the shells does not affect adhesion under the depressurized condition but significantly reduces adhesion under no pressure, leading to even higher tunability (almost infinity). The enhanced adhesion of a depressurized shell is found to be a combined effect of dry adhesion and suction. These shell grippers are shown to be effective in the universal manipulation of various objects with wide ranges of weight, shape, surface roughness, and mechanical compliance. The proposed depressurized soft shells provide a promising robotic gripping platform for industrial adoption. 

Abstract The ability to control adhesion on demand is important for a broad range of applications, including the gripping and manipulation of objects in robotics and manufacturing, and the temporary attachment of wearable devices. Despite recent advances in tunable adhesive materials, most existing solutions have modest adhesion strength and are limited by a compromise between the maximum and minimum adhesion, where increased strength prevents the release of lighter objects. To overcome these challenges, thermally responsive polymers, which can exhibit both high stiffness and a large reduction in stiffness via heating, have the potential to enable strong and tunable adhesion. Here, a microstructured composite adhesive with high strength (>2 MPa) and dynamically tunable adhesion (16×) is realized using a solvent‐assisted molding technique. The adhesive consists of an array of composite micropillars whose small scale and material composition enable strong and tunable adhesion. While thermally actuated systems often have slow response times, it is shown that miniaturization allows response times to be reduced to <1s for heating and <10s for cooling. These strong, fast, and dynamically tunable adhesives offer advantages over existing solutions and can be manufactured for practical adoption through the scalable solvent‐assisted molding technique.